Does it have to be REAL CLOSE?

[Teammuir1]

Re: Does it have to be REAL CLOSE?

it says they are a 40 mercury..
WOW..
maybe I just need to get a NEWER MOTOR,....

 

[SigSaurP229]

Re: Does it have to be REAL CLOSE?

Sure you have modified it with casting decks and added alot of things and increased the weight of the hull substantially. Now the 33 hp can't keep up and I surely wouldn't add anymore Hp because its not just about weight of the motor it is also about thrust of the motor. From 33 Hp to 70 Hp is substantially going to increase thrust, and that amount of thrust may just snap the transom off of the back of the boat.

 

[Silvertip]

Re: Does it have to be REAL CLOSE?

The "rule of thumb" is to install the engine initially so the AV (anti ventilation plate) not cavitation (two different things) so it is flush to 1-inch above the keel. You then test the boat with what you consider an average load while carefully using the trim control while watching the tach and speedometer. Without either one you can't determine performance so the next best option would be to obtain a GPS (hand held will do). You experiment with trim. To extract the last bit of performance from the boat you need to experiment with height. You go up one hole at a time until you experience prop slip or loss of water pressure or both. Then go back down one hole. Keep in mind that moving an engine up and down is not a 10 minute job and optimizing a setup involves lots of trial and error. Fact is, you can't hardly go wrong at flush to 1-inch above the keel and then call it good.

 

[Teammuir1]

Re: Does it have to be REAL CLOSE?

I PERSONALLY have done nothing to the boat
the boat as you see it is how my grandfather made
it some 30 yrs ago....
as I stated earlier.. he claims that he actually pulled
a ski'er on the back of it.....
I am telling every one ( RIGHT NOW ) that is impossible
the boat does not go fast enough...

The motor has 4 different places were I can adjust
I already have done that and it does not change a thing.

I am thinking that the motor must be tired..
it starts great and runs great... but it might just be TIRED..
I have not done a compression test.. I could do that....maybe tomorrow.

 

[d.boat]

Re: Does it have to be REAL CLOSE?

I was waiting to see who was going to pipe and and be the bad guy here.....

Post #8

 

[F_R]

Re: Does it have to be REAL CLOSE?

teammu...You probably don't want to hear this, because you say the motor runs good, just no power. Y'know what?? I suspect it isn't running on both cylinders. They will run just fine on one, but no power. Check it out before swapping motors. It should be easy for it to pull a skier.

BTW, a 33hp is old school design and will not work well with the plate an inch above the bottom. In fact, not well with it being flush either. An inch below is more like it. It will cavitate and ventilate like crazy if raised up too high.

 

[jdsgrog]

Re: Does it have to be REAL CLOSE?

I agree with F_R. I have a '67 33hp and it ran fine with one cylinder, but didn't go past 10mph. I've got a Lund s-14 that I modified (not as much as that jon you have) and with me and my gear alone in the boat, I get about 26-27mph (1000lbs total weight) and with one extra person and his gear I get about 24-25mph (Add about 200lbs).

Go to the Johnson forums and see some of the diagnostics you need to do on that motor (compression, spark, fuel, etc.) I'll almost guess you are not getting spark on one cylinder.

 

[Teammuir1]

Re: Does it have to be REAL CLOSE?

So if in fact it will run on one cylinder and it runs good on one cylinder then in fact that just might be whats happening....
I went to the shop and picked up my Compression tester...TACHOMETER...I have a HEAT GUN....( to test the temp of both cylinders ).... I will be taking my GAMIN ( NUVI ) GPS..... ( for speed )
so I will hopefully figure out whats going on.....
This motor is a 68 model and only owned by my grandfather...
as strange as it sounds from the year of 68 to 81... this motor was
sitting in an OLD shop.. NEVER SOLD....... till my grand dad bought it NEW.
so I know this motor is in GREAT shape... and I am sure things are bound to go wrong sooner or later..... LOL they dont last forever.. lol.
THANKS FOR ALL YOUR IDEAS.. and TIPS......

FR... I am not wanting to put a plate on the back of this boat for
this motor... the only reason I would want a plate.. would be for a BIGGER MOTOR...... to get the plate at or below the bottom of the boat.....

I was always told the best rule of thumb is keep it even... MINE with the 33 Johnson is even with the bottom of the boat....
is it better for the plate to be an inch lower than the boat?
has any one tested this?

 

[Teammuir1]

Re: Does it have to be REAL CLOSE?

I am curious..
can I connect a CAR ( Automotive ) TACH
to this BOAT ????
IF I can.. can someone tell me were to connect to the
MOTOR?

 

[jdsgrog]

Re: Does it have to be REAL CLOSE?

The 33 is a great motor. It's pretty fool proof and easy to work on.

I don't believe a car tach would work. In fact, there really isn't a tach made for this motor. I've been searching around all over the place. The only tach that everyone recommends is a Tiny Tach, and you have to call the company to get the proper one.

 

[d.boat]

Re: Does it have to be REAL CLOSE?

...I was always told the best rule of thumb is keep it even... MINE with the 33 Johnson is even with the bottom of the boat....
is it better for the plate to be an inch lower than the boat?
has any one tested this?

I would think that if your grandpa was pretty happy with the performance, the general setup is not the main issue. YOu might be able to tweak it, but I'd bet you'd be spending a lot of time getting just a bit, if anything.

Get on the general mechanical diagnostics - post on the johnson/evinrude forum with your general concern about performance and those good folks will give you the abc's (compression, spark, fuel) and get that thing back up to par quickly. Good luck, please keep updating.

(I'm still curious about the HP capacity of the boat although it sounds like you're putting the more HP idea on hold for the time being).

 

[F_R]

Re: Does it have to be REAL CLOSE?

Plate?? I was speaking of the anti-cavitation plate. It is supposed to be below the bottom of the boat with those old motors. Yes, you can raise it up till you get excessive cavitation if you want to. But I'm telling you those motors were originally designed for wood boats with keels. Sure you can run it a bit higher, depending on the boat.

See the picture? Below the bottom.

 

[Teammuir1]

Re: Does it have to be REAL CLOSE?

Well I just want to thank each and everyone that has takin
the time to write on this thread....
I honestly appreciate it....
I was on the lake yesturday while I was still getting E-mails and
my phone ringing...from friends and family I was pulling in some REAL NICE FISH
( check out the pics )
I also had the chance to test some things on the boat but after catching those LUNKERS.... I honestly wanted to get them Home FAST.
so here is what I actually did...
GPS says I was going a steady 16mph so that was on the way to my ( HONEY HOLE ) lol
after catching the fish my wife and I drove back to the lakes channel to do some more testing....I have the motor in the most outward position... thas what other guys do that have electric Trim... trim it out to achieve max HP
so for the sake of the test I lowered the motor to the transom.
and drove it once again.. NO change in speed....still 16mph but did change the angle of attack the boat was moving in the water....( I didnt like it )
so we stopped and I moved it back to the most outward position ( 4 hole out ).
tested again.. and still 16mph.
so I took with me HEAT Sink GUN , and Carb Cleaner.
HEAT SINK GUN... I checked to make sure that both cylinders were firing and in deed they were.. I further tested by disconnecting one wire at a time from the cylinder making sure it would not ground while motor was running.
and I see what you guys were talking about this motor did run on only one cylinder... but it was jerky ... once I connected the spark plug wire back up and fired her up again I can HONESTLY say.. its running on both cylinders.
so for the next test I was at WOT and reached back and lightly sprayed carb cleaner near the CARB..... to only find out that the motor started to BOG BAD.... ( SO the motor is getting enough fuel that it needs and WANTS )
so I am lost here... the only thing I do not know.. is the RPM and that sure would help me out... I am thinking about buying another prop....
if I knew what the original one was ( pitch ) I could determine what might help me for top end speed... but there again I dont want to OVER REV the motor.. so again I come back to the TACH situation....
well I went back to the boat ramp tied up at the doc.... and SHARED my CATCH STORIES with a couple of gentlemen that put in the same time we did that morning... and sure enough they didnt have the same luck I did ( LOL )
isnt it fun to catch great fish... ( lol )
once the fish stories stopped I installed brand new PLUGS...and went back out and tested again... I was surprised.. to find out.... that when I took out the bottom plug... the Porcalin was cracked... I was optamistic... and proceeded back out to make another test pass... and I now get 17mph STEADY.... Rock STEADY.....
any more thoughts?

 

[d.boat]

Re: Does it have to be REAL CLOSE?

... the only thing I do not know.. is the RPM and that sure would help me out... I am thinking about buying another prop....
if I knew what the original one was ( pitch ) I could determine what might help me for top end speed... but there again I dont want to OVER REV the motor.. so again I come back to the TACH situation.......

Someone above mentioned Tiny Tach. Get one.

 

[Teammuir1]

Re: Does it have to be REAL CLOSE?

I think I will look into buy this one....
http://cgi.ebay.com/ebaymotors/Smal...mdZViewItemQQitemZ160468062746QQptZGoQ5fKarts